Professor Waterman

Cascading Style Sheets (CSS) is a language that works with HTML documents to define the way content is presented. The presentation is specified with styles that are placed directly into HTML elements, the head of the HTML document, or separate style sheets.

Style Sheets contain a number of CSS rules. Each rule selects elements in an HTML document. Theses rules then define how elements will be styled. Any number of HTML files can be linked to a single CSS file.

Browser style sheets — Browser apply style sheets to all Web documents Although these style sheets vary from browser to browser, they all have common characteristics, including black text, blue links, and purple visited links. These are referred to as default browser style sheets.

User style sheets – A user is anyone who looks at your website. Most modern browsers allow users to set their own style sheets within their browser. These style sheets will override the browser ’ s default style sheets – for that user only.

Authored style sheets — The author is the person who develops the website — you! As soon as you apply a basic style sheet to a page, you have added an author style sheet. Author styles generally override user styles, which override browser styles. See chart below: Browser Style sheet User Style sheet Author Style sheet Web Page

Easy to maintain — The power of CSS is that a single CSS file can be used to control the appearance of multiple HTML documents. Changing the appearance of the entire site can be done by editing one CSS file rather than multiple HTML documents.

Smaller files size — CSS allows authors to remove all presentation from HTML documents, including layout tables, spacer images, decorative images, font, colors, widths, heights, and background images. Presentation can then be controlled by CSS files. This can dramatically reduce the files sizes of HTML documents.

Increased Accessibility — CSS, combined with well-structured HTML documents, can aid devices such as screen readers. With presentational markup removed, the only thing a screen reader encounters is structural content. CSS also can be used to increase the clickable area of the links, as well as control line height and text line lengths for users with motor skill cognitive difficulties.

Different Media — CSS can be styled specifically for different media, including browsers, printers, handheld devices, and projectors — without changing the content or document structure in any way.

More control over typography — CSS allows authors to control the presentation of the content with properties such as capitalization, uppercase, lowercase, text-decoration, letter-spacing, word- spacing, text – indent, and line height. CSS can also be used to add margins, border, padding, background color, and background images to any HTML elements